#include<iostream>
#include<string>
using namespace std;
int main(){
	string s;
	getline(cin,s);
	int left = 0,right = s.size()-1,flag = 0;
	while(left <= right){
		if(s[left] == s[right]){
			flag = 1;
		}
		else {flag = 0; break;} 
	}
	if(flag == 1) cout << "yes";
	else cout << "no";
	return 0;
}
